In the study of electronic materials and processes for fabricating such materials into an electronic structure, a specimen of the electronic structure is frequently used for microscopic examination for purposes of failure analysis and device validation. For instance, a specimen of an electronic structure such as a silicon wafer is frequently analyzed in scanning electron microscope (SEM) and transmission electron microscope (TEM) to study a specific characteristic feature in the wafer. Such characteristic feature may include the circuit fabricated and any defects formed during the fabrication process. An electron microscope is one of the most useful equipment for analyzing the microscopic structure of semiconductor devices.
In preparing specimens of an electronic structure for electron microscopic examination, various polishing and milling processes can be used to section the structure until a specific characteristic feature is exposed.
As device dimensions are continuously reduced to the sub-half-micron level, the techniques for preparing specimens for study in an electron microscope have become more important.
SEM has a large interaction volume and collects mixed information from the surface of the inspected wafer and from deeper portions of the inspected wafer. TEM, and especially cross sectioning based TEM, enables to acquire high resolution information from sub-surface regions of the wafer. TEM requires to generate an electron transparent thin sample, and then extract the thin sample. The extraction of the sample is time consuming and can damage the thin sample.
There is an ongoing need for methods and systems for generating thin samples from wafers for improved analysis of a wafer and especially to provide a reliable and fast automatic process for generating this samples and analyzing them.